CVE-2019-0690 in Windows
Summary
by MITRE
A denial of service vulnerability exists when Microsoft Hyper-V Network Switch on a host server fails to properly validate input from a privileged user on a guest operating system, aka 'Windows Hyper-V Denial of Service Vulnerability'. This CVE ID is unique from CVE-2019-0695, CVE-2019-0701.
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Analysis
by VulDB Data Team • 08/01/2023
The vulnerability described in CVE-2019-0690 represents a critical denial of service weakness within Microsoft Hyper-V Network Switch functionality that specifically affects host server systems running virtualized environments. This flaw manifests when the Hyper-V Network Switch component fails to adequately validate input data originating from a privileged user operating within a guest virtual machine environment. The issue creates a scenario where malicious or compromised guest operating systems can potentially exploit this validation gap to disrupt normal operations of the host server's network infrastructure. The vulnerability operates at the hypervisor level, making it particularly dangerous as it can affect the stability and availability of multiple virtual machines running on the same physical host. The flaw specifically impacts the network switching capabilities of Hyper-V, which serves as the foundational networking component for virtual machine communication and external connectivity.
The technical implementation of this vulnerability stems from insufficient input validation mechanisms within the Hyper-V Network Switch module that handles network traffic between virtual machines and external networks. When a privileged user within a guest operating system sends malformed or specially crafted network packets through the virtualized network interface, the host system's network switch component does not properly sanitize or validate these inputs before processing them. This lack of proper validation allows the malicious input to potentially cause the network switch to crash or enter an unstable state, effectively denying service to legitimate network traffic. The vulnerability operates with the privilege level of a guest user, meaning that exploitation does not require administrator-level access on the host system, making it particularly concerning for multi-tenant environments. According to CWE classification, this vulnerability maps to CWE-20: Improper Input Validation, which is a fundamental weakness in software design that allows malicious inputs to disrupt system operations.
The operational impact of CVE-2019-0690 extends beyond simple service disruption to potentially compromise entire virtualized infrastructures, especially in data center and cloud computing environments where Hyper-V hosts manage multiple virtual machines. When the network switch fails, all virtual machines sharing that host's network resources experience connectivity issues, which can cascade into broader system outages depending on the criticality of the affected services. The vulnerability affects systems running various Windows Server versions including Windows Server 2016, Windows Server 2019, and other supported versions that utilize Hyper-V networking capabilities. Organizations relying on virtualization for business continuity face significant operational risks as this vulnerability can be exploited by attackers with access to a guest virtual machine, potentially leading to denial of service attacks that impact entire server clusters. The ATT&CK framework categorizes this vulnerability under T1499.004: Endpoint Denial of Service, highlighting its potential for disrupting endpoint services and network connectivity within virtualized environments.
Mitigation strategies for CVE-2019-0690 primarily focus on applying Microsoft security updates and patches that address the input validation weakness in the Hyper-V Network Switch component. Organizations should prioritize immediate deployment of the relevant security patches released by Microsoft, which typically include enhanced input validation mechanisms and improved error handling within the network switch module. Network administrators should also consider implementing additional monitoring and alerting systems to detect anomalous network traffic patterns that might indicate exploitation attempts. The vulnerability can be temporarily mitigated by restricting guest user privileges and implementing network segmentation strategies that limit the potential impact of compromised virtual machines. Security teams should also conduct regular vulnerability assessments of their Hyper-V environments to identify similar validation weaknesses and ensure that all virtualization components are properly updated. Additional defensive measures include implementing network access controls and monitoring for unusual network switch behavior that could indicate the exploitation of this vulnerability. The most effective long-term solution involves maintaining up-to-date security patches and following Microsoft's recommended security practices for virtualized environments while regularly reviewing and updating network security configurations to prevent exploitation of similar input validation vulnerabilities.